Introduction to wastewater
Wastewater means or defines the water that has been used in many different activities such as
domestic, humans, commercial, industries or agricultural activities, surface runoff storm
waters from sewers inflow. It can be also defines as any water that has been adversely
affected in quality by anthropogenic influence or else being contaminated by organic and
inorganic materials ,excessive minerals and heavy metals.
Untreated water generally contains the high amount of organic materials, pathogen
microorganisms usually bacteria, three main nutrients (nitrogen, phosphorus and potassium),
noxious, toxic compound and aesthetically substances. This entails health of humans and is
the environmental hazards and must be convey away from it source and carefully controlled
by treatment before final disposal. The goal among this is to protect the environment, public
and human life in the manner and social – economic concerns as wastewater is the problem.
The measure problem of wastewater in Mars can be solid waste and organic materials from
toilets (flushing), waste from domestic activities (food preparation) since the living
conditions on Mars are not well pleasant, or hospitable for human living in it, people living
Mars (colonists) have to live indoors for some important reasons by that way, they are facing
a major problem of wastewater being resulted from their uses. Therefore it is important to
provide the alternative solutions to wastewater that could provide the better sustainable living
conditions on Mars so that the environment is not damage and resources especial water to
make sure that it is not depleted because water is the natural renewable resource that is the
humans , animals and plants need.
The main aim of treating wastewater is to convert it or make it suitable into effluent that can
be either returned or reversed to water cycle (re- usable) with minimal environmental issued.
Wastewater treatment is the process of making water to be suitable or up to standard for its
applications or transform its back to its natural state. This process is required before water is
used and after it has been used to make sure that its quality is maintained.
According to Mars, using of water should be carefully controlled and maintained. Supply of
water should be carried out by using water supply systems based on the long term bases.
Water supply can use storage and recycling, therefore for this involves the quantity and the
quality of water to be provided, planned Mission duration, expected life cycle cost (including
costs for the probability of loss of crew) and the required water supply reliability.

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Water supply reliability is an important factor in crew safety, as measured by the probability
of loss of crew, it also affect Mission success, as measured by the probability of loss of
Mission. The water system developed international space station could be used on Mars but
designed for microgravity. Since Mars have partial Earth gravity ,water supply technologies
could be used. (Jones, Hodgson, and Kliss, 2014).
If water supplied in the Mars fails than the people living on it will be highly affected in few
days of water depletion. Therefore higher reliability is required and water system on Mars
requires intrinsic hardware reliability and highly controlled system design. The system need
analysing of number of people living in Mars (crew), Mission duration of 18 months, return
delay up to 18 months, water consumption , drinking and food preparation water, urine flush
and wash water. So in order to ensure the safety of crew on Mars, water system should
provide enough water and undergoes the recycling system that is more reliable although this
will be costly.

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Body
Factors about mars: Mars is the place to the tallest mountain in the solar system
Olympus Mons, having largest dust storms which can last for months or even cover the entire
planet and it have approximately the same land mass as the Earth. The seasons are extreme
because it’s nearly around the Sun compared with other planets. The Sun appears about half
the size as it does to Earth at the closest point to Sun. Therefore this planet is quite different,
unfamiliar or unknown environment from other planets. Mars have bad hygiene (contact with
harmful microbes that can cause infections and diseases), starvation and it does allow the
survival of humans, so people are sent to it to do some research and projects but putting
people into it, is risky for their health and safety the one of its which include wastewater.
(Jones, 2014)
The following diagram highlight simplest water system which can be used in Mars to supply
water, maintaining and transforming all used wastewater to potable or safe water for domestic
activities on Mars.

As shown in Figure 1, the water system operates in such a way that atmosphere, water and
wastewater recycling processers are included. Carbon dioxide is vented to the space or
transferred to compressor accumulator and then oxygen is generated and supplied while
Carbon dioxide undergoes the reduction and release CH4 in the atmosphere and generate
Figure 1: Water system architecture that can be used in Mars to supply and maintain water
quality

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hygiene water. All products from atmosphere are transferred to wastewater storage and then
processed by water processor which sent it to potable water storage. Resupply water also
processed before they can be used. Waste from respiration (urine, flush water) together with
other wastewater is combined treated with other solids waste. This system clearly showed
that the Mars atmosphere can be directly used as working gas, which helps to reduce the need
for transportation of gas suppliers and minimize the fresh water demand by recycling forms
of organic or hazardous waste.
Usually water treatment involves technology (wastewater collection pipes and treatment
system), science, engineering and business, it is designed to remove solids, bacterial
pathogens, plants organic and/inorganic compounds. The following are the treatment
strategies which can be used in Mars to secure sustainable living for prolonged missions as it
was mentioned earlier, wastewater treatment methods are broadly classified into physical,
chemical and biological processes by where water is treated and purified for it maintenance.

Based on the above table, the physical processes are usually used in the primary treatment for
removal of insoluble particulate, Chemical used in tertiary treatment for removal of inorganic
nutrients and biological processes are used in secondary treatment of the wastewater for
biological removal of dissolved organic matter, and also can be used in tertiary treatment for
biological removal of inorganic nutrients
Application of treatment methods
The waste management system on spacecraft or space station does not operate in isolation. It
is integrated into other systems associated with the environmental control and life support.
On Space Station, the waste is treated as far as possible. This is relatively easy with air, water
and clothing, but garbage and sewage pose more of a problem. Both are potentially an
infection hazard. (Jones, 2012).
Air on the Space station needs to be circulated all the time, and this is achieved by the air
recirculation system. In this system, dust and microbe particles are removed by drawing
through the filters which are cleaned from time to time. Carbon dioxide is removed and
replaced by oxygen. Gases and vapours that are not normally present in the pure air are
removed. This become industrial processes like cooking, the crew and many other sources.
As far as the of the crew are concerned, removal of microbial particles is very important. The
filters are efficient enough that bacteria, fungal spores and even viruses are removed from the
circulation. Sampling of air is carried out regularly.
Any garbage that contains food or any other damp organic compounds has been rotting from
the moment it became cool enough to eat. Bacteria have been munching their way through it,
micro-fungi and moulds have been dissolving it and spreading their unpleasant juices poon it.
It is possible that creatures like insects and worms have been excreting on it and laying their
eggs on it, all this biological activity has their biological effects. Gases and unpleasant odours
are produced. The life-forms in it are multiplying at an alarming rate and overall, the garbage
is becoming a health hazard. In the right conditions, all this can occur within hours of
disposal.
How can we look after our trash in space for six months or more between garbage
collections?

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Bagging and sealing may be an answer, but gases may pose problems, as completely sealing
the bag may cause the bag to burst because of build-up of gas pressure. In addition, biological
action of the type that occurs in garbage can produce heat, this heat can be so great that it will
spontaneously combust-catch fire. This can happen on the farm to hayricks under same
conditions, where damp hay, microbes and anaerobic conditions conspire together to create
higher temperatures. The similar condition is also possible to happen in garbage.
On Space Station 2020, a minimum of rotting garbage is produced. Disposable food
containers are always washed, dried and then disposed to ultraviolet before being bagged as
inactive garbage. Active garbage, which emits gas is placed on a container that allows gases
to event into the air conditioning system, where there are neutralized. Other garbage
containers include wet containers that take wet chemicals or bio-hazardous materials from the
laboratories which cannot be reprocessed through the waste water system.
Wastewater treatment
In waste water treatment plants, the unit operations and processes described in the previous
sections are grouped together in a variety of configurations to produce different levels of
treatment, commonly referred to as preliminary, primary, secondary and tertiary or advanced
treatment.
1. Preliminary treatment
Preliminary treatment prepares wastewater effluent for further treatment by reducing or
eliminating unfavourable wastewater characteristics that might otherwise impede operation or
excessively increase maintenance of downstream process and equipment. This characteristic
includes large solids and rags, abrasive grit, odours and in certain cases unacceptably high
peak hydraulic or organic loadings. Preliminary treatment process consists of physical unit
operations namely, screening and comminution for the removal of debris and rags. Grit
removal for the elimination of coarse suspended matter, and flotation for the removal of oil
and grease. Other preliminary treatment operations include flow equalization, septage
handling and odour control methods.
2. Primary treatment
Primary treatment involves the partial removal of suspended solids and organic matter from
the wastewater by means of physical operations such as screening and sedimentation. Pre-

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aeration or mechanical flocculation with chemical additions can be used to enhance primary
treatment. Primary treatment act as a precursor for secondary treatment. It is aimed mainly at
producing a liquid effluent suitable for downstream biological treatment and separating out
solids as a sludge that can be conveniently and economically treated before ultimate disposal.
The effluent from primary treatment contains a good deal of organic matter and is
characterized by high biological oxygen demand (BOD).
3. Secondary treatment
The purpose of secondary treatment is to remove the soluble and colloidal organics and
suspended solids that have escaped the primary treatment. This is typically done through
biological processes, namely, treatment by activated sludge, fixed-film reactors, or lagoon
systems and sedimentation.
4. Tertiary/ advanced wastewater treatment
Tertiary treatment goes beyond the level of conventional secondary treatment to remove
significant amounts of nitrogen, phosphorus, heavy metals, biodegradable organics, bacteria
and viruses. in addition to biological nutrient removal processes, unit operations frequently
used for these purposes include chemical coagulation, flocculation and sedimentation,
followed by filtration and activated carbon. Less frequently used processes include ion
exchange and reverse osmosis for specific ion removal or for dissolved solid reduction.
Sewage treatment
Sewage is screened to remove large solid chunks, which are disposed in landfill site. It flows
over to the settlement tank to let the fine particles to settle, the settlement is called the
activated sludge. The supernatant is then percolating filtered and/or aerated. The water can be
filtered again, and then disinfected (chlorinated in most cases). When there is no other
complication, the water is returned to nature back to ecological cycle. The sludge removed
from the settlement is composed of living biological material. A portion of it may be returned
to the aeration tank, but the raw sludge is digested by both microorganisms. Anaerobic
(without oxygen) and aerobic (with oxygen) bacteria digestions are used. At the digestion
state, carbon dioxide, ammonia and methane gases are evolved. Volume of the digested
sludge is reduced, and it is acceptable as a fertilizer supplement in farming.

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Treatment by activated carbon is mostly due to adsorption and absorption. When a chemical
species is adhered to the surface of the solid, it is an adsorption. When partial chemicals
bonds are formed between adsorbed species or when the absorption got into the channels of
the solids, it is called absorption.
Municipality wastewater effluent may contain a number of microorganisms of toxic elements,
some as heavy elements or metals because under practical conditions wastes from all many
small or large and even informal industries are directly discharged into the common sewer
system. These amounts are called trace elements, some removed during treatment while
others persist and cause harm on the living environment. This is what cause harm on our
planet and increase health issues worldwide without people knowing the cause. Sometimes,
water can be treated with wastewater treatment plant and one may think that they are done,
water is clean while there are some surviving organisms that are toxic to the environment and
water users. (Jones, 2013)
Those reckless treatment plants are penalised and sometimes suspended to prolong the
planet’s life. For prolonged life of a planet and its people, the wastewater treatment is needed
in order to secure safe water to be used especially during the draught period of the year.
Although this is a major importance in the planet, there are concerns of the safeness and
sustainable living conditions that are monitored. Firstly, the effluent that is obtained during
the cleaning process should be useful to the environment, like agricultural use by farmers
while making sure it does not affect the living of the people and organisms in the
environment. These effluents are sometimes composted and sold for good use.
When water is being cleaned by the water plant it produces lot of useful microorganisms that
can be used in laboratory and testing of water constituent. When sludge is activated during
the cleaning process, all the microbes or organisms are collected in one side of the plant,
where they are collected and using known characteristics they are tested and identified to be
sold. Wastewater treatment plants can clean up to millions of litres per day of working and
that means more organisms are collected in each day of cleaning. For microbes, all the
treatment plant is suited in isolated places from the living environments, where no one will
easily get infected by smell in wastes. Good hygiene is maintained for people working on the
plant system are always highly recommended to prolong their lives including the
surroundings or visitors

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Conclusion

The world’s freshwater resources are under strain. Reuse of wastewater, in concert with other
water conservation strategies can help lessen anthropogenic stresses arising from over-
extraction and pollution of receiving waters. On the other hand, are concomitant
environmental risks with water reuse such as, pollution and salinization of groundwater and
surface-water, degradation of soil quality and impacts on plant growth, the transmission of
disease via the consumption of wastewater-irrigated vegetables, and even increased
greenhouse gas emissions associated with pumping large volumes of wastewater to an
irrigation district. The significance of such risks will plainly be dependent on the reuse
scheme at hand. Ultimately, the challenge facing wastewater reuse is to minimize such risks
so as to maximise the environmental gain.